| Recent years, with the increasing development of economic and social, peoples living standards have a significant improvement and more and more people began to focus on food safety. Foods are always been spoilaged during its production and distribution stage due to some internal or external factors. Therefore, how to contral the growth of microorganism and maintain the quality of foods have become an important issue in today’s food research field, and the active packaging is also emergence and developed gradually in this background.In this research, polyvinyl alcohol(PVA) was selected as membrane material, nano-montmorillonite(MMT), potassium sorbate and citric acid(CA) were selected as active ingredients, and the modified PVA films were prepared by flow-casting method. Firstly, different concentrations of MMT were used to modified the PVA film and the modified MMT-PVA film’s packaging properties were researched. Secondly, the basic properties of MMT blend potassium sorbate modified PVA films were researched. Then the modified antibacterial PVA packaging flims were used to packaged snakehead during cold storage, and their preservation properties were investigated. Lastly, the basic properties and the effect on preservation properties of semi-dried fish of the modified CA-PVA films were investigated. The main conclusions are as follows:(1) The DK4 model of MMT had a good consistency with PVA which made the modified PVA films more dense and homogeneous. By studying the properties of the flims, such as characterization, mechanics, optics, water absorption, thermal stability and so on, showed that the thermal stability and the determination of tensile strength of the modified PVA films were increased, but their elongation at break, water absorption, water vapor permeability, light transmittance were reduced. The experiment results showed that the PVA films added with 1% MMT had the best modified effects.(2) The antibacterial polyvinyl alcohol(PVA) nanocomposite packaging films incorporated with 1% montmorillonoid(MMT), 1% potassium sorbate, 1% MMT + 1% potassium sorbate and 1% MMT + 2% potassium sorbate, respectively, were prepared by flow-casting method. The efficiency of the antibacterial PVA nanocomposite films in preserving the quality of snakehead during cold storage was assessed with water-holding capacity(WHC), pH, thiobarbituric acid-reactive substances(TBARS), total volatile basic nitrogen(TVB-N), total plate count(TPC), and K value. The results indicated that the PVA nanocomposite packaging film incorporated with 1% MMT + 2% potassium sorbate has the best modified effects which can extend shelf-life of snakehead to 3-4 d during cold storage at 4 °C, so it has an effective preservation effect.(3) By adjusting the heating time, heating temperature, stirring speed and other parameters, the regularity of the preparation of the modified PVA colloid was found. The basic properties of modified CA-PVA films were studied using the optical and mechanical parameters, and the antifungal effects were studied using the preservation experiment of semi-dried fish. The acidic antifungal modified PVA films obtained all had good optical and mechanical properties. For the antifungal effects in preservation of semi-dried fish during storage period, the modified PVA films all showed better antifungal effects than the control group, among which the antifungal capacity of the films modified with 2% CA was the best. The modified CA-PVA films had certain regularity in its preparation process and showed good antifungal effects in packaging semi-dried fish. |
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